It is well known that various eye imaging and analysis technology, such as wavefront imaging, can be used to design and/or select a lens design for a given patient, whether for contacts or glasses. For contact lenses that are worn directly on the eye, it is also known that the physiology of the patient's eye itself, of the patient's eyelid, and the interaction between the two can affects the actual positioning of the lens upon the eye. Often, these factors result in the selected lens orienting itself upon the eye in a less than optimal manner, such as laterally offset from the intended position or at an angular orientation relative to what was intended. This results in less than optimal vision through that lens since the lens is not positioned as designed.
In current practice, an eye care practitioner may attempt to correct these errors by viewing the selected contact lens on the patient's eye, often with the assistance of fiducial, or orientation marks scribed, printed, or otherwise produced upon the lens, and using experience and judgment in viewing the error in position to select another lens that when placed on the eye would better account for the position errors. Typically, another standard or stock lens is then selected for the patient and the process repeated until the eye care practitioner is satisfied with the performance of chosen lens. As this is a manual process dependent on the eye care practitioner's visualization and judgment, the next selected lens may not be optimal for the patient. Further, lenses are often produced without such fiducial marks, rendering it much more difficult and subject to error in the selection process.
The present invention provides a system and method to more precisely measure positional errors of a contact lens on a patient's eye, providing the ability to select or design a subsequent lens for that patient that will better account for such errors.